Torquoselective ring opening of fused cyclobutenamides: evidence for a cis,trans-cyclooctadienone intermediate.

ABSTRACT: Electrocyclic ring opening of 4,6-fused cyclobutenamides 1 under thermal conditions leads to cis,trans-cyclooctadienones 2-E,E as transient intermediates, en route to 5,5-bicyclic products 3. Theoretical calculations predict that 4,5-fused cyclobutenamides should likewise undergo thermal ring opening, giving cis,trans-cycloheptadienones, but in this case conversion to 5,4-bicyclic products is thermodynamically disfavored, and these cyclobutenamides instead rearrange to vinyl cyclopentenones.

SUBMITTER: Wang XN 

PROVIDER: S-EPMC4353010 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature